KIT cars are great for engineers and skilled enthusiasts. While all the pieces are provided for you, there’s nothing to stop you from altering the recipe as you see fit. For some, this will be as simple as an engine swap or a change of wheels.

For Duncan Cowper, however, the freedom of a kit car led him to create a take on the Lotus Seven-inspired Dax Rush unlike anything we’ve ever seen before.

Harlow-based Cowper, who once worked at Dax and currently works with world-class motorsport engineer Geoff Page on various projects, decided to build the ultimate version of the Rush.

By all accounts, he seems to have succeeded.

This fire-breathing, all-carbon version, dubbed the ‘F1 Turbo 1300’, features a 1,300cc Suzuki Hayabusa engine mated to a massive turbocharger sourced from a 1986 Benetton Formula One car. According to Cowper, this combination is good for 500bhp on race fuel and more than 380bhp on regular, from-the-pump petrol.

With what is by all accounts an ‘old-school’ turbo and a relatively long gear ratio, you’d expect plenty of turbo lag to become evident in Cowper’s pride and joy. However, this isn’t the case. We had the unique opportunity to witness the car – which has achieved over 160mph at Lotus’s Hethel Test Track – performing high-speed laps at Rye House Kart Raceway, and it leapt from super- tight hairpin corners with incredible acceleration.

We asked Cowper how this was possible. ‘It’s down to the electronics on it. The ECU is from Life Racing, and it’s the same system they put on current Le Mans prototypes and very similar to what Nissan ran on their DeltaWing project.

‘If you watch the boost graph on gear changes, you will not see any dip in boost.

‘Because the engine’s quite high-revving and there’s a lot of gas flowing through it as a result, it keeps the turbo spooled almost all the time with no need for an anti-lag system.’

The turbo would have run five bar of pressure in the Benetton B186 Formula One car during qualifying sessions, but it produces a ‘sedate’ 1.6 bar in Cowper’s Hayabusa-engined project.

However, even with the turbo having a slightly easier life in the Dax Rush, it still propels the 535kg car to some incredible performance figures.

At the concrete runways of RAF Elvington, on road tyres, the Rush completed a quarter of a mile in 10.9 seconds, coming across the line at 140mph. The car has also been clocked from 0-100mph in just 5.6 seconds, which is only a tenth of a second slower than the Bugatti Veyron.

Of course, all of this straight-line performance needs to be matched with handling and braking ability. Cars such as the Rush are usually very light on their feet, but with the incredible level of power solely going to the rear wheels, Cowper felt that aerodynamic aids were necessary.

The rear and front wings, the latter of which wasn’t present on the day we took a look at the car, are self-developed, while stopping power is provided by a set of Formula Three brakes.

With a unique set of assets and mind-boggling performance, the Dax Rush F1 Turbo 1300 is perhaps the most impressive ‘Seven-esque’ kit car in the world, and certainly one of the most spectacular road-legal cars in the UK.

With expertise from Cowper’s vast list of engineer comrades evident throughout the car and its highly fettled Hayabusa engine, it’s a formidable feat of engineering and a symphony of turbo-whistle and tyre-squealing.